Rock Identifier

Category

Mineraloid (Human Made Geological Specimen)

Browse mineraloid (human made geological specimen) specimens identified by the Rock Identifier community.

Ocean Jasper (SiO2 (Silicon Dioxide) - Chalcedony variety) — mineral

Ocean Jasper

SiO2 (Silicon Dioxide) - Chalcedony variety

Mixed River Pebbles (including Unakite and Jasper) (Polymineralic geological specimens) — igneous and sedimentary

Mixed River Pebbles (including Unakite and Jasper)

Polymineralic geological specimens

igneous and sedimentary

Petrified Wood (Silicified Wood (primarily SiO2)) — sedimentary

Petrified Wood

Silicified Wood (primarily SiO2)

Milky Quartz (Quartz (Silicon Dioxide, SiO2)) — mineral

Milky Quartz

Quartz (Silicon Dioxide, SiO2)

Fluorite (Purple variety) (Calcium Fluoride (CaF2)) — mineral

Fluorite (Purple variety)

Calcium Fluoride (CaF2)

Granite Cobble (Phaneritic plutonic rock (dominated by Quartz, Feldspar, and Mica)) — igneous

Granite Cobble

Phaneritic plutonic rock (dominated by Quartz, Feldspar, and Mica)

Milky Quartz (Silicon Dioxide (SiO2)) — mineral

Milky Quartz

Silicon Dioxide (SiO2)

Quartz (Iron-stained) (Silicon Dioxide (SiO2)) — mineral

Quartz (Iron-stained)

Silicon Dioxide (SiO2)

Polished pink feldspar or quartz pebble (uncertain) (Likely microcline feldspar (KAlSi₃O₈) or quartz (SiO₂), with iron-oxide inclusions) — mineral

Polished pink feldspar or quartz pebble (uncertain)

Likely microcline feldspar (KAlSi₃O₈) or quartz (SiO₂), with iron-oxide inclusions

Quartzite Pebble (Metamorphosed Quartz Sandstone (SiO2)) — metamorphic

Quartzite Pebble

Metamorphosed Quartz Sandstone (SiO2)

Petrified Wood (Silicified Wood (primarily SiO2)) — fossil

Petrified Wood

Silicified Wood (primarily SiO2)

Porphyritic Basalt (or Andesite) containing Augite (Porphyritic Mafic Volcanic Rock) — igneous

Porphyritic Basalt (or Andesite) containing Augite

Porphyritic Mafic Volcanic Rock

Sandstone (Muddy/Silty Variety) (Arenite with high silt/clay content (clastic sedimentary rock)) — sedimentary

Sandstone (Muddy/Silty Variety)

Arenite with high silt/clay content (clastic sedimentary rock)

Limonite (FeO(OH)·nH2O (Hydrated iron oxide)) — mineral

Limonite

FeO(OH)·nH2O (Hydrated iron oxide)

Sandstone (Sandstone (composed predominantly of Quartz, SiO2, with Feldspar and Clay minerals)) — sedimentary

Sandstone

Sandstone (composed predominantly of Quartz, SiO2, with Feldspar and Clay minerals)

Magnetite with Serpentine (Magnetite (Fe3O4) in Serpentine Matrix) — mineral

Magnetite with Serpentine

Magnetite (Fe3O4) in Serpentine Matrix

Fuchsite (Green Muscovite in Quartz) (K(Al,Cr)2(AlSi3O10)(OH)2 - Chromium-rich Muscovite) — metamorphic

Fuchsite (Green Muscovite in Quartz)

K(Al,Cr)2(AlSi3O10)(OH)2 - Chromium-rich Muscovite

Blue Calcite (Calcium Carbonate (CaCO3)) — mineral

Blue Calcite

Calcium Carbonate (CaCO3)

Rounded gray pebble, likely basalt or fine-grained volcanic rock (Probable basalt; exact identification is uncertain from the photograph) — igneous

Rounded gray pebble, likely basalt or fine-grained volcanic rock

Probable basalt; exact identification is uncertain from the photograph

Diamond (appearing as a jewelry centerpiece) (Diamond (Formula: C)) — mineral

Diamond (appearing as a jewelry centerpiece)

Diamond (Formula: C)

Quartz-veined Basalt (Amygdaloidal or Porphyritic Basalt with Silicon Dioxide (SiO2) vein) — igneous

Quartz-veined Basalt

Amygdaloidal or Porphyritic Basalt with Silicon Dioxide (SiO2) vein

Sandstone Pebble (Arenite (SiO2 with minor mineral cements)) — sedimentary

Sandstone Pebble

Arenite (SiO2 with minor mineral cements)

Rounded gray river pebble, likely basalt or andesite (Fine-grained mafic to intermediate volcanic rock; commonly basalt (plagioclase + pyroxene, sometimes olivine)) — igneous

Rounded gray river pebble, likely basalt or andesite

Fine-grained mafic to intermediate volcanic rock; commonly basalt (plagioclase + pyroxene, sometimes olivine)

Weathered sandstone or quartz-rich sedimentary pebble (Indeterminate lithic fragment; likely quartz arenite (sandstone)) — sedimentary

Weathered sandstone or quartz-rich sedimentary pebble

Indeterminate lithic fragment; likely quartz arenite (sandstone)

Pyrite (Iron Sulfide (FeS2)) — mineral

Pyrite

Iron Sulfide (FeS2)

Quartzite (Metamorphic Rock (Mainly SiO2)) — metamorphic

Quartzite

Metamorphic Rock (Mainly SiO2)

Chert (Jasper) (Silicon Dioxide (SiO2)) — sedimentary

Chert (Jasper)

Silicon Dioxide (SiO2)

Sandstone (Arenite (SiO2 primarily)) — sedimentary

Sandstone

Arenite (SiO2 primarily)

Petoskey Stone (Hexagonaria percarinata) — fossil

Petoskey Stone

Hexagonaria percarinata

Chert (Yellow Jasper variant) (Microcrystalline Quartz (SiO2)) — sedimentary

Chert (Yellow Jasper variant)

Microcrystalline Quartz (SiO2)

Granite (Granite (composed primarily of Quartz, Alkali Feldspar, and Plagioclase)) — igneous

Granite

Granite (composed primarily of Quartz, Alkali Feldspar, and Plagioclase)

Granite Pebble (Granite (Felsic Intrusive Igneous Rock)) — igneous

Granite Pebble

Granite (Felsic Intrusive Igneous Rock)

Obsidian (Volcanic Glass (Amorphous Silicon Dioxide , SiO2)) — igneous

Obsidian

Volcanic Glass (Amorphous Silicon Dioxide , SiO2)

Gold Nugget (Native Gold (Au)) — mineral

Gold Nugget

Native Gold (Au)

Ferromanganese Nodule (Polymetallic Nodule (composed primarily of MnO2 and Fe2O3)) — sedimentary

Ferromanganese Nodule

Polymetallic Nodule (composed primarily of MnO2 and Fe2O3)

Small polished pink-and-white mineral pebble (Likely rose quartz or pale pink quartz; exact identification is uncertain from the image) — mineral

Small polished pink-and-white mineral pebble

Likely rose quartz or pale pink quartz; exact identification is uncertain from the image

Vesicular basalt (likely weathered lava rock) (Basalt, predominantly calcium-rich plagioclase, pyroxene, and commonly olivine; vesicular texture from gas bubbles) — igneous

Vesicular basalt (likely weathered lava rock)

Basalt, predominantly calcium-rich plagioclase, pyroxene, and commonly olivine; vesicular texture from gas bubbles

Green Aventurine (Silicon Dioxide (SiO2) with inclusions of Fuchsite (K(Al,Cr)2AlSi3O10(OH)2)) — metamorphic

Green Aventurine

Silicon Dioxide (SiO2) with inclusions of Fuchsite (K(Al,Cr)2AlSi3O10(OH)2)

Clear Quartz (Rock Crystal) (Silicon Dioxide (SiO2)) — mineral

Clear Quartz (Rock Crystal)

Silicon Dioxide (SiO2)

Dark basalt (likely vesicular basalt) (Basalt; chiefly plagioclase feldspar, pyroxene, and commonly olivine (approx. SiO₂ 45–52%)) — igneous

Dark basalt (likely vesicular basalt)

Basalt; chiefly plagioclase feldspar, pyroxene, and commonly olivine (approx. SiO₂ 45–52%)

Pyrite (Iron Sulfide (FeS2)) — mineral

Pyrite

Iron Sulfide (FeS2)

Pyrite (Fool's Gold) (Iron Sulfide (FeS2)) — mineral

Pyrite (Fool's Gold)

Iron Sulfide (FeS2)